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By E Niva

The IsaMillÖ is challenging the way that plants are designed and operated. This paper challenges existing designs of concentrator flow sheets, particularly focusing on magnetite circuits.   From what has started out as a small scale ultra fine grinding mill in the pharmaceutical and pigment industries, it has been redesigned and improved upon for mineral processing, and has been the mainstay of fine grinding applications for over ten years. These applications have required energy efficient grinding to succeed, and have been predominately in the base metals industry.   Further development of the IsaMillÖ has now resulted in the machines being able to treat larger tonnages, with higher capacity motors. This development, along with the introduction of purpose designed ceramic media, has allowed the mill to treat courser feed sizes. At the same time, the mill still offers highly efficient grinding, and has enabled it to be operated in coarser tertiary and secondary grinding applications.   The acceptance of the mill in coarser applications, predominately in base metals and PGM applications, has enabled the IsaMillÖ to be a serious contender for beneficiation in other minerals. One such application is the potential for IsaMillsÖ to be part of magnetite flow sheets, which are being considered in Australia to meet the growing iron demand of China. The high energy efficiency of the IsaMillÖ compared to conventional technologies, as well as the smaller infrastructure requirements, provides a great opportunity to reduce the power intensity of magnetite circuits.   This paper will examine the use of IsaMillÖ technology in conventional grinding applications, including recent testwork in a primary grinding base metal circuit, as well as testwork on magnetite ore comparing a lab scale IsaMillÖ with a lab scale Tower Mill.   The growing demand for minerals over the next decade, coupled with higher energy cost, will result in energy efficient technology, such as the IsaMillÖ, being included in standard circuit design.

Jan 1, 2008

Comparing Energy Efficiency of Multi-Pass High Pressure Grinding Roll (HPGR) Circuits With increased emphasis on reducing costs and carbon emissions in mineral processing, it is becoming essential to employ the most efficient comminution devices and to use them to maximum effect. High pressure grinding rolls (HPGR) are considered highly efficient compared with other devices, however their relative efficiency in multi-HPGR circuits is less well understood. A series of comminution tests was carried out to evaluate three multi-pass HPGR circuits and a jaw crusher-ball mill circuit. Combinations of HPGR units (1.0 m and 0.25 m diameter), jaw crushers and Bond ball mills were used to grind a 32 mm top size porphyry copper feed (BBWI = 12.1) to a product P80 size of about 150 ¦m. Up to three passes of HPGR were used in each circuit, with energy measurement and size analysis at each point in the comminution process. The energy efficiencies of individual comminution stages and of the overall circuits were quantified and evaluated using three different approaches. The operating work index method for comparing comminution energy efficiency underestimated HPGR performance due to the large amount of fines generated. The -75 ¦m efficiency factor and F50/P50 reduction ratio interpolation methods both give a fairer measure because they better take into account the amount of fines generated by HPGR. The results show that the relative comminution efficiencies of the three multi-pass HPGR circuits tested differ by as much as 22%, providing insights as how to best employ HPGR in a comminution circuit. The most energy efficient of the circuits tested was a three-pass HPGR circuit with a 1.0 m diameter roll on the first pass in closed circuit with an 8 mm screen followed by a second and third pass in a 0.25 m roll.

Sep 13, 2010

By L. Bbosa

Positron Emission Particle Tracking (PEPT) and the Discrete Element Method (DEM) are used to investigate Power Draw in a laboratory scale tumbling mill. The mill is run dry in batch mode at different speeds using mono-size charge of glass beads, and is mounted along with a torque transducer to measure power. Particle tracking information from PEPT is used to reconstruct the motion of glass beads and infer the overall charge behavior, while DEM is employed to simulate particle motion and interaction, with collision mechanics calculated using the Hertz-Mindlin contact model. For PEPT and DEM data, the product of torque and average angular velocities in discrete cells are accumulated to obtain mill power. This method is found to be within statistical agreement with measured power for all tests. Spatial distributions plotted from this approach highlight the regions of the mill that draw the greatest power. A second technique to obtain Power Draw from DEM data which sums particle forces against the mill geometry is similarly found to accurately predict mill power with lower statistical error. Keywords: Power Draw, PEPT, DEM

Sep 1, 2012

By G. Morin, F. Chiesa, B. Duchesne

The Quality index is a useful tool allowing to assess the metallurgical quality of aluminium AlSiMg foundry alloys (A356/357). Its value is calculated from the ultimate tensile strength and elongation; it increases with the metallurgical quality of the casting, i.e. with finer dendrites, lower microporosity and inclusion count and lower iron content. This Quality index does not depend on the degree of temper applied during the heat treatment (aging time and temperature). After defining the Quality index, it will be explained how it can be predicted from the knowledge of the local solidification conditions obtained from modelling. The paper will then present four case studies of castings for which the prediction of the Quality index by modelling was made. These case studies from different authors will involve the three most common casting processes used for producing high integrity aluminium castings, namely: sand casting, permanent mould casting and investment casting (lost wax). In all cases, the accuracy of the prediction will be assessed by comparing the predicted Quality index distributions to the experimental values based on the published measured values of the local tensile properties.

Jan 1, 2006

By Gerald W. Cormick

In a complex society such as ours, the range of "negotiating" relationships is constantly increasing. These negotiating relationships have emerged as a direct result of the diffusion of power or influence to new sectors and emerging concerns. Even within organizations, the myth of the authority-based heirarchical structure has given way to the reality of constant negotiations between superior and subordinate and with peers in the organizational structure. In the broader context, the corporate organization finds it necessary to reckon and often negotiate with organized employees, suppliers, buyers, government agencies and a range of organized private interests ranging from minority groups to environmental organizations. In response to this diffusion of power and the conflicts which it has engendered, a variety of conflict avoidance, conflict managing or conflict resolution techniques has developed. The purpose of this paper is to attempt to differentiate between some of the conflict intervention approaches which have appeared "on the market", and to suggest three bases for selecting among them: 1. The "role" of the conflict intervenor; 2. How far the conflict has developed; and 3. The breadth and impact of the issues involved.

Jan 1, 1979

By M. Rossi

Geologic ore controls are usually interpreted and modeled from cross sections and plans, as they are critical to construct meaningful and accurate ore reserves models. The geologic boundaries are often modeled as two-dimensional surfaces or three-dimensional solids and used as hard boundaries to constrain the grade estimates. In many cases, the geologic model is the most important factor in estimating the mineralized tonnage predicted by the reserves model, since it is generally drawn to separate the volumes of mineralized and waste material within the deposit. Because geologic models are interpreted from widely spaced drill hole data, the accuracy of the contacts of the different zones modeled could be poor. The lack of accuracy in the definition of geo-logic zones can have a significant impact on a resource model. In this paper it is shown that the geologic interpretation can and should be checked for potential biases. In particular, an unbiased overall volume of the original drill hole information with respect to the resulting solids and codes assigned to the block model is sought. In addition, geostatistical conditional simulations can be used to simulate the geologic attributes modeled, thus providing an alternative view of the geology, and a measure of the uncertainty of the geologic boundaries. The simulated geologic model provides an assessment of the impact of alternative geologic interpretations on the over-all uncertainty of the reserves model. In the case study presented here, the uncertainty of the geologic model is quantified for a difficult-to-model, high-grade copper deposit in northern Chile.

Jan 1, 2004

By V. A. Leão, A. M. Silva, S. M. Bertolino, B. C. S. Ferreira, D. Guimarães

Although not considered a high risk pollutant as compared to toxic metals and acidity, environmental agencies worldwide are proposing regulations to control sulphate in effluents and drainages by setting a threshold value varying between 250 mg/L and 500 mg/L. The aim of this study was thus to compare four different techniques for removing sulphate ions from mining/metallurgy effluents. The first alternative studied was sulphate removal by precipitation as ettringite. Treating a synthetic solution containing 1650 mg/L sulphate at 22±1 ºC resulted in removals close to 85% during continuous precipitation. Sulphate sorption was also investigated using three different ion exchange resins as well as limestone. Fixed bed experiments produced sulphate loadings of up to 70 mg SO4 2-/L resin, at pH 2.0. In neutral wastewaters, limestone is also a potential adsorbent producing a maximum particle loading of 19 mg/g. Sulphate sorption on limestone seems to be an alternative to treating mine waters with sulphate concentrations below the 1200-2000 mg/L range, where lime precipitation is not effective. Subsequently, sulphate removal by sulphate reducing bacteria was also investigated and it was observed that reactor’s hydrodynamic conditions and the choice of substrate are important factors for the process. The different technical aspects of each technology are addressed.

Jan 1, 2014

By J. Noll, J. A. Organiscak, A. B. Cecala

"In recent years, significant strides have been made to optimize the design of filtration and pressurization systems used on enclosed cabs of mobile mining equipment to reduce respirable dust and other contaminants and provide the best air quality to the equipment operators. This synergetic effort has involved original equipment manufacturers building mining equipment, manufacturers of heating, ventilation, and air conditioning systems for mobile equipment, filtration and pressurization system manufacturing companies, as well as the National Institute for Occupational Safety and Health, and other government organizations. Considering all the advances made in this area over the last decade, one aspect that NIOSH still needs to assess is the longevity of optimal cab performance with respect to the quality (filtering efficiency) of the filters used in filtration and pressurization systems. In today’s culture, most health and safety professionals automatically believe that HEPA quality filters need to be used to provide the greatest level of protection to workers. Researchers at the Office of Mine Safety and Health Research for NIOSH hypothesized that HEPA quality filters may not be optimal for the mining industry and speculated that MERV 16 rated filters would be more appropriate in most cases. In order to test this hypothesis, NIOSH performed a two-year study comparing both HEPA and MERV 16 quality filters on two pieces of underground limestone mining equipment, being a roof-bolter and face drill machine. Testing showed at the 95 pct. confidence level that there was no statistical difference between the two efficiency filters on both pieces of mining equipment. Since the MERV 16 rated filters were less restrictive and provided greater cab pressure, and since they did not have to be replaced as often as the HEPA quality filters, researchers concluded the MERV 16 filters were the optimal choice for both pieces of mining equipment in this case study comparative analysis. INTRODUCTION When most health and safety professionals today think about filtration efficiencies and their correlation with protecting workers’ health, the normal assumption is the higher the efficiency of a filter, the greater the protection afforded to the workers. The next logical step is to believe that HEPA filters deliver the greatest protection for workers because they provide the highest filtering efficiency. Obviously high-efficiency intake filters are a necessity for an effective cab filtration and pressurization system on mobile mining equipment, but what is the optimal filter efficiency rating for achieving high levels of cab protection factor performance over the service life of filters? To address this question, the National Institute for Occupational Safety and Health (NIOSH) has performed an in-depth laboratory research study over the years simultaneously with numerous field studies to retrofit used enclosed cabs on mobile mining equipment with newer and more effective filtration and pressurization systems."

Jan 1, 2016

By Ryan L. Veenstra

This paper presents a modelling study of a cemented paste backfill in an underground stope. The model was developed to help provide a better understanding of what is happening in the stope during the filling stage of the stope. In order to do this, the model incorporates the paste rise rate, stope geometry, and time-dependent input parameters. This paper looks at the effect of geometry in two parts. The first part compares a series of simple rectangular stope models. These models differ in size both in two and three dimensions. The second part compares the results of four 2D models together and then to the field instrumentation data. Part of this section introduces the geometry and instrumentation within the test stope.

Jun 1, 2012

By S. Stuurman

Inorganic acids such as sulphuric acid have found use together with certain reducing agents in leaching of copper-cobalt oxide ores. These reagents are not ideal due to the adverse effect the inorganic acids generally have on the environment and the high costs of the reducing agents. In this study a copper-cobalt oxide ore from the Central African Copperbelt was leached in two different environments; sulphuric acid in conjunction with hydrogen peroxide as a reducing agent and tartaric acid. The effects of acid concentration, reducing agent concentration, and temperature were independently determined for both leaching environments. The sulphuric acid concentration was varied between 0.4 M and 1.2 M and the concentration of hydrogen peroxide between 4.0 M and 6.5 M, while the tartaric acid concentration was varied between 0.15 M and 0.35 M. The temperature was varied between 20°C and 50°C. The results showed that the extraction of both copper and cobalt increased with sulphuric acid concentration, reaching a peak at approximately 0.8 M and then decreasing at higher acid concentrations. A similar increase and decrease in metal extraction was observed when the reducing agent was increased. In leaching with tartaric acid, the extraction of cobalt was much higher than that of copper, although extraction of both metals increased with acid concentration. Additions of small amounts of hydrogen peroxide were found to increase cobalt extraction in tartaric acid but had a minimal effect on copper. An increase in the solution temperature had a significant effect in the organic acid environment, with the effect on cobalt extraction being much more pronounced than on copper.

Jan 1, 2014

By Andrew B. Cecala, Emily J. Haas, Jay F. Colinet

A sociotechnical system (STS) creates a framework that allows an examination of how social and technical factors affect organizational outcomes within a specific environmental context. STS has been rigorously studied with a primary research focus addressing worker-technology interactions. Although these interactions are important, the social processes and interactions that occur whenever any technical or environmental change is introduced into the system have been undervalued. If social processes are better understood, mining organizations could efficiently prepare and stabilize for such changes. With this goal in mind, we sought to extend STS theory through applying principles of meta-design to analyze the results of two case study interventions. Specifically, we studied the impact of an unregulated dust control technology (the Helmet-CAM) and a regulated dust control technology (the Continuous Personal Dust Monitor) on factors within an STS including employees’ knowledge of, communication about, and use of technology to mitigate respirable dust sources. The results are presented in a way that first, addresses the overarching principles of meta-design STS including organizational participation, flexibility, and communication and second, examines how technology implementation processes differ when the organization is complying with a formal, higher-level requirement. Results show that a prominent focus on the social factors within an STS framework could help reduce unpredictability on the technical side and may improve communication within the system to help reduce adoption time, especially if and when accompanying a new, formal work process.

By Andrew B. Cecala, Emily J. Haas, Jay F. Colinet

A sociotechnical system (STS) creates a framework that allows an examination of how social and technical factors affect organizational outcomes within a specific environmental context. STS has been rigorously studied with a primary research focus addressing worker-technology interactions. Although these interactions are important, the social processes and interactions that occur whenever any technical or environmental change is introduced into the system have been undervalued. If social processes are better understood, mining organizations could efficiently prepare and stabilize for such changes. With this goal in mind, we sought to extend STS theory through applying principles of meta-design to analyze the results of two case study interventions. Specifically, we studied the impact of an unregulated dust control technology (the Helmet-CAM) and a regulated dust control technology (the Continuous Personal Dust Monitor) on factors within an STS including employees’ knowledge of, communication about, and use of technology to mitigate respirable dust sources. The results are presented in a way that first, addresses the overarching principles of meta-design STS including organizational participation, flexibility, and communication and second, examines how technology implementation processes differ when the organization is complying with a formal, higher-level requirement. Results show that a prominent focus on the social factors within an STS framework could help reduce unpredictability on the technical side and may improve communication within the system to help reduce adoption time, especially if and when accompanying a new, formal work process.

By Andrew B. Cecala, Emily J. Haas, Jay F. Colinet

Researchers from the U.S. National Institute for Occupational Health and Safety (NIOSH) studied the impact of an unregulated dust control technology (the Helmet-CAM) and a regulated dust control technology (the continuous personal dust monitor) within a sociotechnical system (STS) framework to mitigate respirable dust sources. The results address how to best incorporate the overarching principles of meta-design STS during the technology integration process. Specifically, quantitative and qualitative data show that a prominent focus on the social factors within an STS framework could help reduce organizational unpredictability and may improve communication within the system to help reduce technology adoption time.

By M. Dupuis, V. Bojarevics

It is well known that horizontal current density in the metal pad contributes greatly to the generation of MHD driven bath-metal interface wave. It is possible to compute very accurately the metal pad current density using a very detailed finite element model [1], but a MHD model must be compatible to this level of mesh refinement and to recalculate the current distribution at each time step, including the full busbar supply system. The accuracy of the instability prediction of the cell depends on the accuracy of the metal pad current density calculation. This study presents the comparison of the metal pad current density calculation of the detailed finite element model and the MHD-Valdis model for different metal pad heights and ledge thickness. It also presents the corresponding cell MHD stability predictions.

Jan 1, 2006

By A. Mainza, H. Hill, L. Bbosa

"The main objective of ore breakage characterization is to quantify the relationship between the energy supplied for breakage and the size of the resultant progeny. In this study, the ore breakage characteristics of drill core particles and crushed particles were compared. Single impact breakage tests were conducted on a basalt ore sample using the JK rotary breakage tester. The size-dependent model by Shi and Kojovic was used to fit the breakage data because the effect of initial particle size is accounted for in the model. It was found that crushed particles consistently gave a higher degree of brokenness than drill core particles and the differences were attributed to the internal structure of the particle. Drill core particles contain a lower crack density (paths of weakness) than crushed particles which have been pre-weakened during the crushing process. An increase in crack density is directly related to a decrease in the minimum threshold energy. Upon application of a stressing force above the stress threshold, particles with a higher crack density will fracture more easily because of a higher rate of crack propagation due the numerous paths of weakness available. It was therefore concluded that under the same conditions, drill core particles are more competent than crushed particles. INTRODUCTION Comminution devices have commonly been reported as being the largest energy consumers in mineral processing circuits (Napier-Munn, 2015). Cleary (1998) reported that the inefficiency of comminution devices is a result of less than 5% of the supplied energy being utilized for breakage, with the majority being expended as heat and noise. With steadily declining fossil fuel supplies and a looming global energy crisis, the mineral processing industry has increased its focus on energy reduction measures. Ore breakage characterization plays a critical role in the design and optimization of comminution circuits (Tavares and King, 1998). The main objective of ore breakage characterization is to empirically quantify the relationship between the energy supplied for breakage (specific input energy) and the size of the resultant progeny through laboratory particle breakage tests (Napier-Munn, 1996). Commonly used laboratory breakage devices include the Drop Weight Tester (DWT), Split Hopkinson Pressure Bar (SHPB) and more recently, the JK Rotary Breakage Tester (JKRBT). Typically, a standard single impact breakage test procedure consists of a matrix of experiments on particles in four to five narrow size fractions each tested at low, medium and high energy levels. The resultant progeny of each test is sized to obtain a particle size distribution (PSD) from which the degree of breakage, usually in the form of a t10 value (percentage of the progeny material that passes 1/10 of the feed size) can be obtained for each size fraction and energy level (Napier-Munn, 1996)."

Jan 1, 2018

By J. Petersen, A. E. Lewis, J. Chivavava

Rare earth elements (REEs) have special properties that prompted their extensive use in high-tech applications. The demand for REE has, therefore, increased over the past years, resulting in the supply risk of the materials. Extraction from non-conventional low-grade ores, like easy-to-mine ion adsorption clays (IACs), by hydrometallurgical methods is being explored to supplement the supply of REEs. The extraction of REEs from low tenor IAC leach solutions requires enrichment using cost-effective methods such as precipitation. Therefore, the aim of this study was to understand the recovery of REEs from IAC leach solutions using various reagents for precipitation. In the first part of the study, recoveries of REEs from IAC leach solutions through direct precipitation using H2C2O4 and NH4HCO3, as well as antisolvent crystallization using C2H5OH, were predicted via thermodynamic modelling using OLI Stream Analyzer. Verification experiments were then conducted through the use of an agitated reactor. Simulation results showed that high yields of REEs were possible using each of the reagents, but large quantities of C2H5OH were required. Experimental results confirmed the high yields predicted from simulations. Precipitation with H2C2O4 was found to selectively recover REEs while rejecting Al. However, utilization of NH4HCO3 and C2H5OH resulted in the co-precipitation of Al. Furthermore, the yield of Y from antisolvent crystallization was significantly lower than the theoretical value. The product recovered from antisolvent crystallization consisted of well faceted, large crystalline particles, which filtered faster than the fine, amorphous REE carbonates recovered using NH4HCO3. REE oxalates were crystalline, larger than the REE carbonates and, overall, showed the highest filtration rate.

Dec 11, 2024

By R. Patterson

Tracer gas sampling methods are useful for monitoring ventilation systems, especially in remote or inaccessible areas, and can be utilized for analysis of the ventilation system immediately following a mine emergency. However, the success of this technique is largely dependent on the accuracy of release and sampling methods. Analysis of sampling methods is crucial for rapid response and dependable results during emergencies. For the purpose of this study, four well-accepted sampling techniques currently used in the mining industry were compared using solid-phase microextraction (SPMe) fibers with sulfur hexafluoride (SF6), an industry standard, as the tracer gas. Current sample collection techniques include plastic syringes, glass syringes, Tedlar bags and vacutainers. SPMe fibers are used in a variety of industries, from forensics to environmental sampling, and are a solventless method of sampling analytes. To analyze these sampling methods, samples were taken from a 0.01 % standard mixture of SF6 and nitrogen and analyzed using electron capture gas chromatography. A relative standard error of less than 10% validated results to compare the accuracy of various methods. The technical and practical issues surrounding each sampling method were also observed and discussed.

Jan 1, 2011

By L. Garycki, P. Poks, R. Urbaniak, T. Gabka

In 2016 at Głogów Copper Smelter KGHM Polska Miedź S.A., after shutting down the shaft furnaces new FSF was launched. Currently, it is the only smelter with two direct to blister flash smelting furnaces in operation. The main difference between the vessels are the dimensions and production capacity. The new furnace design output is about 30% higher compared to the old flash smelting furnace working for 40 years. The paper presents a comparison of both FSFs operation, differences in technology and the way to optimize the process to maximize efficiency. INTRODUCTION KGHM Polska Miedź S.A. is the only company in Poland (eastern part of Europe) that extracts and processes copper ores. It is located in the south west of Poland and this region is called the "Copper Basin”. KGHM PM S.A. consists of three underground mines: Lubin, Polkowice-Sieroszowice, Rudna, concentrator plants, a tailings pond plant, three copper plants: Legnica, Głogów and Cedynia wire rod plant in Orsk. The publication relates to the operation of the furnaces in Głogów (the plant in Głogów consists of Głogów 1 and Głogów 2 which form integrated smelting and refining facilities). In 2016, after closure of the shaft furnaces technologies in the Głogów 1, a new FSF commenced operation. The simplified process flow sheets are given in Figure 1 and 2. Technological schemes are similar, but due to the differences in them, they will be discussed separately. Głogów 1 Enriched ores are discharged and directed to the feed preparation plant. Delivered concentrates are built up on the three bedding aisles in appropriate proportions. The concentrates are distributed in even layers in one of the three aisles. Aisle emptying is done with a blending machine which cuts across the concentrate layers and collects thus blended material, sending it via belt conveyors to a storage bin. From the cross- blending machine and conveyor assembly, the mixture of concentrates is directed to drying in the steam dryer. Part of the charge is directed to the FSF and part to the roaster for carbon elimination. Known in the world roasters are used to eliminate sulfur compounds or arsenic. In the case of KGHM deposits, the aim of the process is to reduce the energy value of the feed by eliminating carbon and converting sulfur from sulfide to sulfate. Changing the nature of exothermic to endothermic material is crucial in the case of furnace operation with design performance. Roaster is a separate furnace with an innovative character.

Jan 1, 2019

By Elaine Ellingham, Francis T. Manns

"Abstract -The Orostar and Scadding were two small gold mines owned and operated by Orofino Resources Limited. Conventional statistical treatment indicates an identical arithmetic mean grade of 0.22 oz/T Au for both mineable reserves. Further, the deposits are both shown to have cut weighted average reserve grade of 0.21 oz/T. Orostar mined out at 0.206 oz/T and Scadding at0.156 oz/TAu . The combined exploration and development database contained 1394 fire assays, more than enough for statistical confidence in a normal distribution. Therefore this study was initiated to determine, if possible, why the mill head grades were lower than the averages and to experiment with several methods to determine whether a reliable statistical mill head grade estimation method would emerge. Despite the identical reserve grades, distinct differences in the grade distribution histograms are present. By studying the arithmetic and log-normal grade distribution s, with some attention to South African practices, this paper reports on those differences which may account for the considerable divergence in the mill head grades. Furthermore, this study casts considerable doubt on the industry standard method of cut weighted averages.The global mill head grades of the two deposits have been derived from the arithmetic average grades by graphic means. This precise method of mill head grade prediction, if applied to complex orebodies, could permit selective grade control and result in direct cost savings by allowing the operator to detect false value stopes, benches or levels and emphasize reliable regions of not only gold mines, but also uranium or base metal deposits."

Jan 1, 1992

By Alessandro Blasi, Massimo Morgana, Corradino Sposato, Pietro Garzone, Giuseppe Devincenzis

A comparison among (2-ethylhexyl)-mono (2-ethylhexyl) ester Phosphonic acid (P507), Secondary-octyl phenoxy acetic acid (CA-12) and Bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex272), in heavy rare earths separation via hydrometallurgical processes has been investigated. The separation coefficients, , were obtained and the extraction selectivity has been evaluated using a mixture of heavy rare earths from Samarium to Ytterbium. The experimental results indicated that P507 and Cyanex 272 display a greater affinity for heavier rare earths while CA12 proved to be more effective for the lighter rare earth metals.

Jan 1, 2014